\newcommand{\blah}{command definition
  goes here
and here}

\begin{equation}
  f(x) = \left(... some long expression here ...
    + more stuff here
  + more stuff here \right)
\end{equation}

Lorem ipsum {\color{red} dolor sit amet, consetetur sadipscing elitr, sed diam
  nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed
diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum.} Stet
clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
